from io import BytesIO

from django.http import HttpResponse
from django.views.generic import View

from tmstiler.django import DjangoRasterTileLayerManager

from .models import Measurement


class SafecastMeasurementsTileView(View):

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # create per month layers
        months = Measurement.objects.order_by("date").values_list('date', flat=True).distinct()
        layers = OrderedDict()
        legend = Legend()
        for m in months:
            qs = Measurement.objects.filter(date=m)
            month_layername = m.strftime("%Y%m")
            layers[month_layername] = {
                        "pixel_size": 1500,  # size of bin in meters
                        "point_position": "upperleft",
                        "model_queryset": qs,
                        "model_point_fieldname": "location",
                        "model_value_fieldname": "value",
                        "legend_instance": legend,  # returns a hslcolor_str
                        }
        self.tilemgr = DjangoRasterTileLayerManager(layers)

    def get(self, request):
        layername, zoom, x, y, image_format = self.tilemgr.parse_url(request.path)
        mimetype, tile_pil_img_object = self.tilemgr.get_tile(layername, zoom, x, y)
        image_encoding = image_format.replace(".", "")  # change ".png" to just "png"
        # pillow img.tobytes() doesn't seem to work, workaround to serve raw bytes via BytesIO()
        image_fileio = BytesIO()  
        tile_pil_img_object.save(image_fileio, image_encoding)
        image_fileio.seek(0)
        return HttpResponse(image_fileio, content_type=mimetype)